The deaths of two young women, miscarriages and birth defects in Brazil have been linked to Oropouche virus, a little-known disease spread by midges and mosquitoes.
A surge in cases has been recorded in the country this year – 7,284, up from 832 in 2023. Many have been recorded in areas that have not previously seen the virus.
A total of 8,078 cases had been confirmed in Brazil, Bolivia, Peru, Colombia and Cuba by the end of July, with doctors in the region urged to be vigilant.
The climate emergency is likely to be driving the insects that spread the virus to new areas, experts warned, while genetic changes in Oropouche itself may play a role.
The first known deaths anywhere in the world, of two women aged 21 and 24 in Bahia state, were announced by Brazil’s health ministry on 25 July. They each developed sudden symptoms – which can include fever, body aches and headaches – that led to fatal bleeding. A potential third linked death, of a 57-year-old man, is under investigation.
One of the women who died had twice sought help from health facilities but had been discharged. Márcia São Pedro, epidemiological surveillance director for Bahia, said: “This is related, I believe, to the fact that people assume everything is dengue. And because dengue is well known, they hydrate and send the patient home. We need to understand that this is not the case. We are in a different situation now.”
In June officials reported a pregnant woman lost her baby at 30 weeks’ gestation, with Oropouche virus subsequently detected in samples from the umbilical cord and organs. A miscarriage at eight weeks’ gestation was also linked to the virus.
Tests in four newborn babies with microcephaly, a condition in which the baby’s head is smaller than expected, also indicated the presence of antibodies to Oropouche virus – although those tests do not prove definitively that the virus caused the birth abnormalities.
Deaths and miscarriages are “really standout things that we don’t really associate with this virus”, said Alain Kohl, professor of virology at Liverpool School of Tropical Medicine (LSTM), and an expert i